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https://issues.apache.org/jira/browse/BEAM-4018?focusedWorklogId=94366&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-94366
]
ASF GitHub Bot logged work on BEAM-4018:
----------------------------------------
Author: ASF GitHub Bot
Created on: 23/Apr/18 23:25
Start Date: 23/Apr/18 23:25
Worklog Time Spent: 10m
Work Description: jkff commented on a change in pull request #5175:
[BEAM-4018] Add a ByteKeyRangeTracker based on RestrictionTracker for SDF
URL: https://github.com/apache/beam/pull/5175#discussion_r183565970
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/splittabledofn/ByteKeyRangeTracker.java
##########
@@ -0,0 +1,159 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.transforms.splittabledofn;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.MoreObjects;
+import java.util.Arrays;
+import javax.annotation.Nullable;
+import org.apache.beam.sdk.io.range.ByteKey;
+import org.apache.beam.sdk.io.range.ByteKeyRange;
+import org.apache.beam.sdk.transforms.DoFn;
+
+/**
+ * A {@link RestrictionTracker} for claiming {@link ByteKey}s in a {@link
ByteKeyRange} in a
+ * monotonically increasing fashion. The range is a semi-open bounded interval
[startKey, endKey)
+ * where the limits are both represented by ByteKey.EMPTY.
+ */
+public class ByteKeyRangeTracker extends RestrictionTracker<ByteKeyRange,
ByteKey> {
+ private ByteKeyRange range;
+ @Nullable private ByteKey lastClaimedKey = null;
+ @Nullable private ByteKey lastAttemptedKey = null;
+
+ private ByteKeyRangeTracker(ByteKeyRange range) {
+ this.range = checkNotNull(range);
+ }
+
+ public static ByteKeyRangeTracker of(ByteKeyRange range) {
+ return new ByteKeyRangeTracker(ByteKeyRange.of(range.getStartKey(),
range.getEndKey()));
+ }
+
+ @Override
+ public synchronized ByteKeyRange currentRestriction() {
+ return range;
+ }
+
+ @Override
+ public synchronized ByteKeyRange checkpoint() {
+ checkState(lastClaimedKey != null, "Can't checkpoint before any key was
successfully claimed");
+ ByteKeyRange res = ByteKeyRange.of(next(lastClaimedKey),
range.getEndKey());
+ this.range = ByteKeyRange.of(range.getStartKey(), next(lastClaimedKey));
+ return res;
+ }
+
+ /**
+ * Attempts to claim the given key.
+ *
+ * <p>Must be larger than the last successfully claimed key.
+ *
+ * @return {@code true} if the key was successfully claimed, {@code false}
if it is outside the
+ * current {@link ByteKeyRange} of this tracker (in that case this
operation is a no-op).
+ */
+ @Override
+ protected synchronized boolean tryClaimImpl(ByteKey key) {
+ checkArgument(
+ lastAttemptedKey == null || key.compareTo(lastAttemptedKey) > 0,
+ "Trying to claim key %s while last attempted was %s",
+ key,
+ lastAttemptedKey);
+ checkArgument(
+ key.compareTo(range.getStartKey()) > -1,
+ "Trying to claim key %s before start of the range %s",
+ key,
+ range);
+ lastAttemptedKey = key;
+ // No respective checkArgument for i < range.to() - it's ok to try
claiming keys beyond
+ if (!range.getEndKey().isEmpty() && key.compareTo(range.getEndKey()) > -1)
{
+ return false;
+ }
+ lastClaimedKey = key;
+ return true;
+ }
+
+ /**
+ * Marks that there are no more keys to be claimed in the range.
+ *
+ * <p>E.g., a {@link DoFn} reading a file and claiming the key of each
record in the file might
+ * call this if it hits EOF - even though the last attempted claim was
before the end of the
+ * range, there are no more keys to claim.
+ */
+ public synchronized void markDone() {
+ lastAttemptedKey = range.getEndKey();
+ }
+
+ @Override
+ public synchronized void checkDone() throws IllegalStateException {
+ checkState(
+ next(lastAttemptedKey).compareTo(range.getEndKey()) > -1,
+ "Last attempted key was %s in range %s, claiming work in [%s, %s) was
not attempted",
+ lastAttemptedKey,
+ range,
+ next(lastAttemptedKey),
+ range.getEndKey());
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(this)
+ .add("range", range)
+ .add("lastClaimedKey", lastClaimedKey)
+ .add("lastAttemptedKey", lastAttemptedKey)
+ .toString();
+ }
+
+ // Utility methods
+ /**
+ * Calculates the next {@link ByteKey} for a given key by incrementing by
one using byte
+ * arithmetic. If the input key is empty it assumes it is a lower bound and
returns the 00 byte
+ * array.
+ */
+ @VisibleForTesting
+ static ByteKey next(ByteKey key) {
+ return key.isEmpty()
+ ? ByteKey.of(0)
+ : ByteKey.copyFrom(unsignedCopyAndIncrement(key.getBytes()));
+ }
+
+ // Following methods cloned from org.apache.hadoop.hbase.util.Bytes
+ /**
+ * @return The value of the input incremented by one using byte arithmetic.
It treats the input
+ * byte[] as an unsigned series of bytes, most significant bits first.
+ */
+ private static byte[] unsignedCopyAndIncrement(byte[] input) {
+ byte[] copy = Arrays.copyOf(input, input.length);
+ if (copy == null) {
+ throw new IllegalArgumentException("cannot increment null array");
+ } else {
+ for (int i = copy.length - 1; i >= 0; --i) {
+ if (copy[i] != -1) {
Review comment:
The number "-1" doesn't look very good in a function called "unsigned..." -
are you sure this is correct? Is there a way to make it more obviously correct?
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Issue Time Tracking
-------------------
Worklog Id: (was: 94366)
Time Spent: 6h (was: 5h 50m)
> Add a ByteKeyRangeTracker based on RestrictionTracker for SDF
> -------------------------------------------------------------
>
> Key: BEAM-4018
> URL: https://issues.apache.org/jira/browse/BEAM-4018
> Project: Beam
> Issue Type: New Feature
> Components: sdk-java-core
> Reporter: Ismaël Mejía
> Assignee: Ismaël Mejía
> Priority: Minor
> Time Spent: 6h
> Remaining Estimate: 0h
>
> We can have a RestrictionTracker for ByteKey ranges as part of the core sdk
> so it can be reused by future SDF based IOs like Bigtable, HBase among others.
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